It is known to provide shuttle valves in which a valve element is slidable between axially aligned bores for alternately opening and closing each axial bore with respect to a transverse port located between the two bores, as for example those disclosed in U.S. Pat. Nos. 2,408,799 and 2,206,957. In such prior arrangements at least one of the axial bores is provided in a sleeve or adaptor that is assembled to a body member and there being a counterbore larger in diameter than the axial bores and in which counterbore the valve element is fitted with a close sliding clearance. However, in such prior arrangements a simple construction is lacking in which the sleeve is mounted so that its bore will be concentric with the other bore to a high degree of accuracy and wherein the sleeve is sealed at at least two locations relative to the body for greater assurance against leakage between the sleeve and body.